#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <malloc.h>
#include <string.h>
#include <sys/socket.h>
#include <resolv.h>
#include <netdb.h>
#include <openssl/ssl.h>
#include <openssl/err.h>

#define FAIL    -1

int OpenConnection(const char *hostname, int port)
{
	int sd;
	struct hostent *host;
	struct sockaddr_in addr;
	if ((host = gethostbyname(hostname)) == NULL)
	{
		printf("Eroor: %s\n", hostname);
		perror(hostname);
		abort();
	}
	sd = socket(PF_INET, SOCK_STREAM, 0);
	bzero(&addr, sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_port = htons(port);
	addr.sin_addr.s_addr = *(long*) (host->h_addr);
	if (connect(sd, (struct sockaddr*) &addr, sizeof(addr)) != 0)
	{
		close(sd);
		perror(hostname);
		abort();
	}
	return sd;
}

SSL_CTX* InitCTX(void)
{
	const SSL_METHOD *method;
	SSL_CTX *ctx;
	OpenSSL_add_all_algorithms(); /* Load cryptos, et.al. */
	SSL_load_error_strings(); /* Bring in and register error messages */
	method = SSLv3_client_method(); /* Create new client-method instance */
	ctx = SSL_CTX_new(method); /* Create new context */
	if (ctx == NULL)
	{
		ERR_print_errors_fp(stderr);
		printf("Eroor: %s\n", stderr);
		abort();
	}
	return ctx;
}

void ShowCerts(SSL* ssl)
{
	X509 *cert;
	char *line;

	cert = SSL_get_peer_certificate(ssl); /* Get certificates (if available) */
	if (cert != NULL)
	{
		printf("Server certificates:\n");
		line = X509_NAME_oneline(X509_get_subject_name(cert), 0, 0);
		printf("Subject: %s\n", line);
		free(line);
		line = X509_NAME_oneline(X509_get_issuer_name(cert), 0, 0);
		printf("Issuer: %s\n", line);
		free(line);
		X509_free(cert);
	}
	else
		printf("No certificates.\n");
}

int main(int count, char *strings[])
{
	SSL_CTX *ctx;
	int server;
	SSL *ssl;
	char buf[1024];
	int bytes;
	char *hostname, *portnum;
	if (count != 3)
	{
		printf("usage: %s <hostname> <portnum>\n", strings[0]);
		exit(0);
	}
	SSL_library_init();
	hostname = strings[1];
	portnum = strings[2];
	ctx = InitCTX();
	server = OpenConnection(hostname, atoi(portnum));
	ssl = SSL_new(ctx); /* create new SSL connection state */
	SSL_set_fd(ssl, server); /* attach the socket descriptor */
	if (SSL_connect(ssl) == FAIL) /* perform the connection */
	{
		printf("Eroor: %s\n", stderr);
		ERR_print_errors_fp(stderr);
	}
	else
	{
		char *msg = "HelloWorld";
		printf("Connected with %s encryption\n", SSL_get_cipher(ssl));
		ShowCerts(ssl); /* get any certs */
		SSL_write(ssl, msg, strlen(msg)); /* encrypt & send message */
		bytes = SSL_read(ssl, buf, sizeof(buf)); /* get reply & decrypt */
		buf[bytes] = '\0';
		printf("Received %d : %s \n", strlen(buf), buf);
		SSL_free(ssl); /* release connection state */
	}
	close(server); /* close socket */
	SSL_CTX_free(ctx); /* release context */
	return 0;
}
